Method and apparatus for data transmission via capacitance sensing device

ABSTRACT

A system made up of a first device which includes a communication interface and a processing device and a second device which includes a touch sensor assembly and a controller, where the controller uses the touch sensor assembly to communicate with the processing device through a capacitor that is jointly formed by the touch sensor assembly and a conductive portion of the communications interface.

RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/870,516, filed on Jan. 12, 2018, which is a continuation of U.S.application Ser. No. 14/609,274, filed on Jan. 29, 2015, now U.S. Pat.No. 9,891,765, issued on Feb. 13, 2018, which is a continuation of U.S.patent application Ser. No. 13/435,890, filed on Mar. 30, 2012, now U.S.Pat. No. 9,013,425, issued on Apr. 21, 2015, which claims the prioritybenefit of U.S. Provisional Application No. 61/602,480, filed Feb. 23,2012, all of which are incorporated by reference herein in theirentirety.

TECHNICAL FIELD

This disclosure relates to the field of touch sensors and, inparticular, to capacitive sensors.

BACKGROUND

Recent developments in touch sensors have begun to add processing ofsignal data to attempt to identify objects. Examples of this include theaddition of large object detection, stylus operation, fat fingerdetection, and grip suppression. However, these methods only identify ageneric class of object and can not distinguish between particularobjects in the class. For example, a finger can not be distinguishedfrom a metal slug, and all large objects are reported using a singleflag, and any associated positional information is typically ignored.

Current touch sensors do allow for general user interaction involvinglocation detection of general objects. However, the user is aware ofwhich particular object is on the screen. When the touch sensor is notcapable of identifying the particular object, information that couldprovide the user a richer user experience is ignored.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings.

FIG. 1 is a simplified cross-sectional view of the touch sensor devicesystem according to an embodiment;

FIG. 2 is a plan view of an embodiment of a touch sensor array;

FIG. 3 is a plan view of a capacitive profile of an object according toan embodiment;

FIG. 4 is a plan view of a capacitive profile of an object according toanother embodiment;

FIGS. 5 and 6 are plan views of high capacitance regions of capacitiveprofiles according to various embodiments;

FIG. 7 is a cross-section view of a capacitive structure according to anembodiment;

FIG. 8 is a cross-section view of a capacitive structure according toanother embodiment;

FIG. 9 is a flow chart of a method for operating a capacitance sensingdevice according to an embodiment;

FIG. 10 is a simplified cross-sectional view of the touch sensor devicesystem according to another embodiment

FIG. 11 is a simplified block diagram of the touch sensor device systemof FIG. 10; and

FIG. 12 is a block diagram illustrating an embodiment of an electronicsystem.

DETAILED DESCRIPTION

Reference in the description to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least one embodimentof the invention. The phrase “in one embodiment” located in variousplaces in this description does not necessarily refer to the sameembodiment.

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the subject matter of the present application. It willbe evident, however, to one skilled in the art that the disclosedembodiments, the claimed subject matter, and their equivalents may bepracticed without these specific details.

The detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow illustrations in accordance with exemplary embodiments. Theseembodiments, which may also be referred to herein as “examples,” aredescribed in enough detail to enable those skilled in the art topractice the embodiments of the claimed subject matter described herein.The embodiments may be combined, other embodiments may be utilized, orstructural, logical, and electrical changes may be made withoutdeparting from the scope and spirit of the claimed subject matter. Itshould be understood that the embodiments described herein are notintended to limit the scope of the subject matter but rather to enableone skilled in the art to practice, make, and/or use the subject matter.

Embodiments of the present invention provide methods for a touch sensor,or capacitive sensing device, to identify and interact with a particularreal world object. Two methods are disclosed—one using a capacitiveprofile for identification and the other using the touch sensor arraytraces for wireless communication.

Various embodiments include a method for touchscreen controller toidentify and interact with a particular real world object. Twoembodiments include one using a capacitive signature for identificationand the second using the touchscreen traces to transmit/receive lowbitrate UART serial date.

In one embodiment a touchscreen may identify particular objectsignatures and thus physical objects may be created with a particularcapacitive signature. In addition to identifying the presence andlocation of an object, the ITO traces of the touchscreen may be used forsimple bi-directional serial communications between real-world objectsand a touchscreen controller (e.g. see 90 of FIG. 11). Enabling atouchscreen to reliably identify and interact with particular real worldobjects opens up new user interface options. Examples may include thefollowing: a cell phone to unlock; the code from an RSA security tokenthat may be transmitted directly into a system through the touchscreen;game pieces on a touchscreen gameboard that may react to placement onthe gameboard using lights, vibration or other methods of signaling auser of an event.

Various embodiments use a capacitive profile to identify a particularobject and may also allow for a particular object to communicate withthe touchscreen controller using a UART or other serial protocol coupledinto the touchscreen traces. Example applications include the following;authentication, asset tracking, Data Matrix applications, game pieces,such as chess pieces where the play does not necessarily have to be viaa touchscreen but may also be implemented using an electronic gameboard.

In another embodiment there may be two objects, one which could beanother touchscreen controller that communicates using a serial protocolover a physical connection via the touchscreen traces. This includescommunicating with a touchscreen device by coupling signals from anotherdevice, in this embodiment other than a stylus, through the touchscreen.

In some embodiments, the ability of the objects to communicate may allowfor a host to create haptics interactions outside the actual frame ofthe device. For example, a real-world game piece may vibrate whencertain game conditions occur, or two devices may synchronize forprecision timing of events, or when meeting a new business contact, youmay transmit your business card, and get theirs by touching the cellphones together.

It should be noted that sensed profiles and serial communication mayapply to any sensing method or conductive material that may be inventedin the future. In other embodiments, the profile and communicationtheory could extend to non-conductive sensing methods. For example, ifthe sensing method uses images to detect objects, this could be modifiedusing LED's (Light Emitting Diodes) to enable a communication channelbetween real world objects and the controller.

In general, the capacitive sensor array 22 is operated by providing asignal to one of the columns 28 of column sensor elements 24 (i.e., TXelectrodes) while grounding the other column sensor 24. Signals aregenerated in the row sensor elements 26 (i.e., RX electrodes) byelectrical coupling of the driven column sensor elements 24 to the rowsensor elements 26. The signal induced in the row sensor elements 26 maychange due to the presence of an object (e.g., a finger) on, or near,that portion of the sensor array 22. The signal change in the row sensorelements 26 is indicative of change in the capacitance between the rowsensor elements 26 and the driven column sensor elements 24 (i.e.,“mutual capacitance”). This process is continuously repeated for each ofthe columns 28 of column sensor elements 24.

In accordance with one aspect of the present invention, an object (e.g.,object 14 in FIG. 1) with a particular capacitive profile, or signature,is placed in proximity to the sensor array 22. The particular layout ordesign of the capacitive profile is used to, for example, transfer data(or communicate) with the capacitance sensing device 12 (FIG. 1).

FIG. 3 illustrates an exemplary capacitive profile 36 of the object 14in FIG. 1. The description of the capacitive profile 36 below refers toportions or regions of the object 14 that have relatively highcapacitance values and those that have relatively low capacitancevalues. However, it should be noted that FIG. 3 may also be understoodto illustrates the capacitance profile 36 of the object 14 as it isdetected by the sensor array 22. That is, FIG. 3 may be understood toillustrate either a side of the object 14 facing the capacitance sensingdevice 12 and/or an arrangement of signals generated by the sensor array22 in response to the object 14 being placed proximate to thecapacitance sensing device 12 (and/or the sensor array 22).

Still referring to FIG. 3, the capacitive profile 36 includes anarrangement of first (or high) capacitance portions (or regions) 38 andsecond (or low) capacitance portions 40. In the depicted embodiment, thefirst capacitance portions 38 include a relative large portion 38 a inthe shape of an “L” with members extending along the top and left edges(as oriented in FIG. 3) of the capacitive profile 36. Portion 38 a isone example of a fiducial element of the capacitive profile 36 which maybe used to allow a capacitance sensing device to establish the size andorientation of the profile being sensed.

The first capacitance portions 38 also include smaller portions 38 b,which in the depicted embodiment take the form of various geometricshapes and/or symbols. As shown, some of the portions 38 b are shaded toindicate a contiguous area with relatively high capacitance values,while others are shown only as outlines of the particular shapes toindicate “hollow” portions of relatively high capacitance values.

As such, the first capacitance portions 38 form various shapes andsymbols of relatively high capacitance portions on the object 14, whichare separated by lower capacitance portions (second capacitance portions40). In particular, it should be noted that in various locations withinthe capacitance profile 36, one of the second capacitance portions 40 ispositioned immediately between two of the first capacitance portions 38.This spatial relationship between the first capacitance portions 38 andthe second capacitance portions 40 may exist along both the x-axis andthe y-axis of the object, as shown by the exemplary orientation of theobject 14 in FIG. 3, such that the capacitive profile is two-dimensional(or 2-D). More particularly, in at least some embodiments, at least oneof the second capacitance portions 40 is positioned between two of thefirst capacitance portions 38 along a first axis (e.g., the x-axis),while at least one of the second capacitance portions 40 is positionedbetween two of the first capacitance portions 38 along a second axisthat is perpendicular to the first axis (e.g., the y-axis). It should benoted how such an arrangement differs from the capacitance profile whichmay be presented by a typical object, such as a finger or stylus, whichtakes the shape of a single, integral region or signal.

In one embodiment of the invention, the shape, size, orientation and/orlocation of the shapes relative to each other, or to a fiducial element,may be used to encode data. In one embodiment, a number of bits may beencoded in the shape, size and/or orientation of a set of predefinedshapes, and a number of bit fields established relative to fiducials. Inthe example illustrated in FIG. 3, nine shapes (formed by the firstcapacitance portions 38 b) shown may correspond to nine bit fields ofencoded data, and sixteen different shape/orientation combinationspossible within a given region may allow four bits of data to beencoded. In such an embodiment, a total of 36 bits may be encoded. Aswill be apparent one skilled in the art, many alternative fiducialpatterns and predetermined shapes, sizes and orientations and/or numbersof regions may be used to encode data.

In one embodiment, the encoded data may be used merely to identify theobject placed on or close to the sensor. In another example, thepatterns may be used to communicate information to the deviceincorporating the touch sensor. In a further example, the data encodedmay be used to identify the user or the device, acting in place of apassword. In another implementation, the data encoded may be used toinitiate a particular function or service.

FIG. 4 illustrates a capacitive profile 36 of the object 14 according toanother embodiment of the present invention. Of particular interest inFIG. 4 is that the smaller high capacitance portions 38 b are arrangedto form a pattern of lines, as opposed to the geometric shapes and/orsymbols shown in FIG. 3. As in FIG. 3, data may be encoded in thepattern via the presence or absence of a high capacitance link betweensecond capacitance portions 40. In the example illustrated, there aretwelve horizontal and twelve vertical boundaries between portions 40,and thus 24 bits of data may be directly encoded in the pattern. FIGS. 5and 6 illustrate further examples of the high capacitance portions 38 bin other shapes and arrangements.

FIGS. 7 and 8 illustrate cross-sections of structures that may be usedto form the capacitive profile(s) 36 described above within the object14. Referring to FIG. 7, a structure 46 is illustrated that includes aconductive substrate (or layer) (e.g., metal) 48 and an alternatingseries of high-K bodies 50 and low-K bodies 52 coupled to a lower sideof the conductive substrate 48. As will be appreciated by one skilled inthe art, the high-K bodies 50 may correspond to the first capacitanceportions 38 of the capacitive profiles 36, while the low-K bodies 52 maycorrespond to the second capacitance portions 40 of the capacitiveprofiles 36. As such, FIG. 7 (and FIG. 8) may be considered to becross-sectional views of the object 14 as it is shown in FIG. 1.

It will also be appreciated that the structure 46 may be arranged toform the 2-D capacitive profiles 36 shown in FIGS. 3 and 4, as well asone-dimensional (1-D) and even three-dimensional (3-D) profiles. In anexemplary 3-D profile, the third dimension may correspond to variationsin the capacitance values of the first capacitance portions 38 (e.g.,the first capacitance portions 38 may include varying degrees of highcapacitance portions, such that some of the first capacitance portions38 have higher capacitance values than others.) It should also beunderstood that the capacitive profile 36 may be further tuned byadjusting the physical dimensions of the high and low-K bodies 50 and52, such as the widths 54 thereof.

FIG. 8 illustrates a capacitive structure 56 according to anotherembodiment. The structure 56 includes a conductive substrate 58, aninsulating material 60, and a series of conductive members 62. As shown,the insulating material 60 separates the conductive substrate 58 fromthe conductive members 62 and separates each of conductive members 62from the adjacent conductive members 62. As will be appreciated by oneskilled in the art, in the embodiment shown in FIG. 8, the conductivemembers 62 may correspond to the first capacitance portions 38 of thecapacitive profiles 36, while the portions of the insulating material 60between adjacent conductive members 62 may correspond to the secondcapacitance portions 40 of the capacitive profiles 36. As with theembodiment shown in FIG. 7, the capacitance profile created by thestructure 56 shown in FIG. 8 may be altered by adjusting the dimensions,such at the widths 64, of the conductive members 62 (thus altering theresistance applied by each conductive member 62).

It should be noted that the embodiments shown in FIGS. 7 and 8 may eachrely on a path to earth ground created by the user holding the metalplate to secure the object in proximity to the capacitance sensingdevice 12.

In operation, when the object 14 is positioned proximate to thecapacitance sensing device 12 (and/or the sensor array 22), thecapacitive profile 36 (e.g., as shown in FIG. 3 or FIG. 4) is detectedby the sensor array 22 is scanned (e.g., by a processing device orcontroller). In particular, the particular shapes, symbols, and/orpatterns formed by the high capacitance portions 38 (and/or portions 38b) may be detected and recognized (e.g., by a processing device) asbeing associated with data (which may in turn be associated with theparticular object 14). In one embodiment, the data is stored in alook-up stored in a memory within the capacitance sensing device 10. Inanother embodiment, the data may be encoded in the shapes, symbols,and/or patterns within the capacitive profile 36. In such an embodiment,the data may be decoded within the capacitance sensing device 12 using,for example, an unlock or decryption key (e.g., by a processing device).

As an example of the type of data that could be associated with theobject, a capacitance sensing device may identify a particular tokenobject before allowing the phone to unlock. For example, the code froman RSA security token could be transmitted directly into a systemthrough the touchscreen. As another example, game pieces on atouchscreen gameboard could react to placement on the gameboard usinglights, vibration or other methods of signaling a user of an event. Inanother example, the data may be used to assist in pairing devices forwireless communication, such as when pairing Bluetooth devices. However,it may also be applicable to Wi-Fi, ZigBee or other wirelesscommunication networks or systems.

In one embodiment, the scanning of the sensor array 22 (FIG. 2) may beperformed in multiple stages, or steps. An embodiment of such a method66 is depicted in FIG. 9. The method 66 begins at step 68 with a basic(i.e., low resolution) scan being performed of the entire sensor array22 (or a first portion of the sensor array 22). Data processing isperformed at step 70 to determine if a suitable object (e.g., one with acapacitive profile such as described above) is in proximity with thesensor array 22. If no such object is detected, at step 72, the method66 returns to step 66.

In one embodiment, the presence of a relatively large high capacitanceportion with a particular shape (e.g., portion 38 a in FIG. 3) may leadto a determination that an object with a capacitive profile has beendetected. Is such an object is detected, the method 66 proceeds to step74.

At step 74, a second scan of the sensor array 22 is performed. In oneembodiment, the second scan is performed at a second, higher resolutionthan the first scan, which may allow for more complex capacitiveprofiles to be used. The second scan may also be performed on only asecond portion of the sensor array 22. For example, with reference toFIG. 3, the first scan (step 68) may be performed over the entire sensorarray 22 and/or the entire capacitive profile 36. However, the secondscan (step 74) may be performed on only the portion of the sensor array22 that corresponds to those portions of the capacitive profile 36 thatinclude portions 38 b (i.e., and not portion 38 a). Thus, the secondscan may be performed on a portion of the sensor array 22 which issmaller, and may overlap, the portion of the sensor array 22 scanned inthe first scan.

At step 76, data processing (e.g., high resolution) is performed, whichincludes determining the data associated with the capacitive profile 36and/or the object 14, as described above.

According to another aspect of the present invention, the sensor array22 is used to exchange data with the object 14 via capacitive coupling.More particularly, the sensor array 22 may be used to communicate dataencoded on a carrier signal via capacitance coupling between the sensorarray and another device. In one embodiment, serial data may becommunicated to the object and/or received from the object using asUniversal Asynchronous Receiver/Transmitter (UART). In oneimplementation, the UART data may be modulated on a carrier; in anotherimplementation, the UART data may be communicated directly.

In such an embodiment, a processing device or a controller coupled tothe sensor array 22 may be configured to provide modulated signals tothe sensor electrodes 24 and/or 26 such that the data (e.g., in the formof modulated signals) is transmitted from the sensor array 22. Likewise,the processing device may be configured to demodulate signals receivedfrom the sensor array 22 as caused by the electrodes 24 and/or 26capacitatively coupling signals emitted from the object 14.

In one application, both the capacitance sensing device and the deviceit is communicating with may share a common electrical ground—forexample, if the user is holding both devices. In this case, thetouchscreen, for example, may be used to form a single plate of a singlecapacitor to communicate data via capacitatively coupled signals betweenthe touchscreen device and another device. In another application, thetwo devices may be electrically isolated from each other (other than viathe capacitative coupling), and in this case, a return signal path maybe required. In one implementation, interleaved, alternating rows orcolumns of the touchscreen may be connected together to form a pair ofcapacitor plates and couple with a corresponding pair or set of plateson the other device. In such an embodiment, a differential signal may betransmitted via the pair of capacitors thus formed between the twodevices.

With reference now to FIG. 10, in such an embodiment, the object 14within a system 10 otherwise similar to that shown in FIG. 1 may have atransceiver (XCVR) (or just a transmitter or just a receiver) 78embedded therein. As such, the object 14 may be device configured forcommunication, and in some embodiments, the object 14 may even take theform of another capacitance sensing device (or a device that includes acapacitance sensing device).

FIG. 11 is a simplified block diagram of a system similar to that shownin FIG. 10. As shown in FIG. 11, the capacitance sensing device 12includes a touch sensor pad (e.g., the touch sensor assembly) 18 and acontroller 80, while the object 14 includes a communications interface82 and a microcontroller (MCU) 84 (e.g., including the XCVR). Within thecapacitance sensing device 12, touch sensor signals 86 andcommunications signals 88 are sent between the touch sensor pad 18 andthe controller 80. In one embodiment, the touch sensor signals 86 andthe communications signals 88 are sent using the same physicalconnections. Within the object 14, communications signals 90 are sentbetween the MCU 84 and the communications interface 82. In oneembodiment, the communications interface 82 may include one or morecapacitors.

A device-object interface 90, through which the data described herein issent, may be formed by the capacitance sensing device 12 and the object14 being in contact or simply within close proximity (e.g., a fewcentimeters). More particularly, in one embodiment, the device-objectinterface 90 may include a capacitor that jointly is formed by thecapacitance sensing device 12 and the object 14. This capacitor mayinclude a first conductor (or plate) formed by the touch sensor pad 18,a second conductor formed by a conductive portion of the communicationsinterface 82, and an insulating material between the first and secondconductors formed by the overlay 20 (e.g., glass), air, and/or a housingof the capacitance sensing device 12.

Examples of the processes that could be implemented using the sensorarray 22 in such a way include, but are not limited to, deviceauthentication/password transfers, mobile payments, access control,electronic business card transfers, or other applications which mayutilize near field communication (NFC).

In one application of this aspect of the invention, user identificationinformation may be communicated in this way. In one particularembodiment, the touchscreen device (i.e., the capacitance sensingdevice) may be used in place of an radio-frequency identification (RFID)or NFC identification badge to authenticate a user to unlock a door oridentify the user to some other access control system. The accesscontrol system may support multiple communication types including butnot limited to RFID and NFC, so that the same access control receivermay be used to provide access to users of RFID cards, NFC-enableddevices, and other suitably configured touchscreen devices.

In another application, this aspect of the invention may be used toauthenticate a wireless device attempting to join a wireless networksuch as but not limited to a Bluetooth, Wi-Fi, or Zigbee network.

In another application of this aspect of the invention, the touchscreendevice may be used to identify the user of the touchscreen device to anautomobile—for example to allow stored settings to be retrieved (e.g.,controlling seat position, mirror angle, in-car entertainment systemsettings, etc.).

In another application, this aspect of the invention may be used toimplement the communications channel of an “electronic wallet” in anequivalent way as is currently implemented using NFC for ePaymentsystems.

Utilizing the sensor array in such a manner may require the object andthe scanning system of the capacitance sensing device 12 to worktogether, sharing the time-sensitive and critical resource of the sensorarray 22. Several methods for sending data on the shared resource (i.e.,the sensor array 22) without conflicts are described below.

A first method involves transmission to the hardware to occur while theprocessor is processing data from the previous scan. A second methodinvolves a communication interface between the two modules. If themodules are on separate silicon, a physical interface may be needed. Ifall modules are collocated in a single chip, then each method simply hasto block execution until critical resource use has been completed.

A third method involves the use of a capacitive profile, along with thetransceiver 78, on the object 14 to signal the device 12 that the object14 includes a transceiver. As such, in one embodiment, the detection ofa particular capacitive profile initiates the wireless communicationbetween the device 12 and the object 14.

Regardless of the method chosen for the device side module, the objectmay require intelligence when deciding when to scan. The object mayglean information about scan rate, by observing multiple scans andtiming between them. There may be a protocol regarding the time sliceinside of the main loop execution available for the real world object totransmit without appearing to be a TX sensor line. Such protocols willbe well known to those skilled in the art, and may include, but are notlimited to RS232, RS485, Hayes Modem command protocols, etc.

Once an object can identify and communicate with a real world object anentire world of new user experiences may be enabled. The ability of theobjects to communicate allows for a host to create haptics interactionsoutside the actual frame of the device. For example, a real-worldgamepiece may vibrate when certain game conditions occur, or two devicescould synchronize for precision timing of events. When meeting a newbusiness contact, a user may transmit a business card, and receive thebusiness card of the contact, by simply touching cell phones together.

The capacitive profile method presented here is used because that is thecurrent best-in-class technology for touchscreen sensing. However, thesame idea of sensed profiles and serial communication may apply to anysensing method, using any conductive material. The profile andcommunication theory may extend to non-conductive sensing methods aswell. If the sensing method instead used images to detect objects, thiscould be modified using, for example, LED's to enable a communicationchannel between real world objects and the controller.

In other embodiments, different materials may be used to form theelectrodes, such as copper, aluminum, silver, or any suitable conductivematerial that may be appropriately patterned. Furthermore, an FPC may beused to form the electrodes. In such an embodiment, the variousconductive layers in the FPC may be appropriately configured to form thearray of electrodes as described above, as well as to form the primarytraces. As such, it should be understood that the electrodes, thetraces, and the insulating material (or body) may all be formed by asingle, appropriately configured FPC. As will be appreciated by oneskilled in the art, such embodiments may be particularly applicable tonon-transparent devices, such as mouse pads, track pads, touch pads,etc. Additionally, in other embodiments, the substrate may be made ofother materials, such as any suitable plastic, including vinyl andpolyamide, which may not be transparent, depending on the particulardevice.

In another embodiment, the sensor may be formed by bonding a glass (orother transparent insulating) lens onto another glass with the sensorpattern disposed on. In yet another embodiment, the sensor may be formedby bonding glass (or other transparent insulating material) onto a sheetof PET containing the sensor pattern.

FIG. 12 illustrates a block diagram of one embodiment of an electronicsystem having a processing device for detecting a presence of aconductive object, and performing the other methods and processesdescribed above, according to an embodiment of the present invention.The electronic system 100 includes a processing device 110, atouch-sensor pad 120, a touch-sensor slider 130, touch-sensor buttons140, a host processor 150, an embedded controller 160, andnon-capacitance sensor elements 170. The processing device 110 mayinclude analog and/or digital general purpose input/output (“GPIO”)ports 107. The GPIO ports 107 may be programmable and may be coupled toa Programmable Interconnect and Logic (“PIL”), which acts as aninterconnect between the GPIO ports 107 and a digital block array of theprocessing device 110. The processing device 110 may also includememory, such as random access memory (“RAM”) 105 and program flash 104.The RAM 105 may be static RAM (“SRAM”), and the program flash 104 may bea non-volatile storage, which may be used to store firmware (e.g.,control algorithms executable by processing core 102 to implementoperations described herein). The processing device 110 may also includea memory controller unit (“MCU”) 103 coupled to memory and theprocessing core 102.

The processing device 110 may also include one or more analog blocksarray coupled to the system bus. The analog blocks array also may beconfigured to implement a variety of analog circuits (e.g., ADCs, DACs,analog filters, etc.). The analog block array may also be coupled to theGPIO 107.

As illustrated, the capacitance sensing circuit 101 may be integratedinto the processing device 110. The capacitance sensing circuit 101 mayinclude analog I/O for coupling to an external component, such as thetouch-sensor pad 120, the touch-sensor slider 130, the touch-sensorbuttons 140, and/or other devices. The capacitance sensing circuit 101and the processing device 110 are described in more detail below.

The embodiments described herein are not limited to touch-sensor padsfor notebook implementations, but can be used in other capacitivesensing implementations, for example, the sensing device may be atouchscreen (or touch screen), a touch-sensor slider 130, ortouch-sensor buttons 140 (e.g., capacitance sensing buttons). In oneembodiment, these sensing devices may include one or more capacitivesensors. The operations described herein are not limited to tabletcomputers, smartphones, touchscreen phone handsets, mobile internetdevices (MIDs), GPS navigation devices, electronic books, notebookpointer operations, but can include other operations, such as lightingcontrol (dimmer), volume control, graphic equalizer control, speedcontrol, or other control operations requiring gradual or discreteadjustments. It should also be noted that these embodiments ofcapacitive sensing implementations may be used in conjunction withnon-capacitive sensing elements, including but not limited to pickbuttons, sliders (ex. display brightness and contrast), scroll-wheels,multi-media control (ex. volume, track advance, etc) handwritingrecognition and numeric keypad operation.

In one embodiment, the electronic system 100 includes a touch-sensor pad120 coupled to the processing device 110 via bus 121. The touch-sensorpad 120 may include a multi-dimension sensor array. The multi-dimensionsensor array includes multiple sensor elements, organized as rows andcolumns, such as the sensor arrays described above and shown in, forexample, FIG. 2. In another embodiment, the electronic system 100includes a touch-sensor slider 130 coupled to the processing device 110via bus 131. The touch-sensor slider 130 may include a single-dimensionsensor array. The single-dimension sensor array includes multiple sensorelements, organized as rows, or alternatively, as columns. In anotherembodiment, the electronic system 100 includes touch-sensor buttons 140coupled to the processing device 110 via bus 141. The touch-sensorbuttons 140 may include a single-dimension or multi-dimension sensorarray. The single- or multi-dimension sensor array may include multiplesensor elements. For a touch-sensor button, the sensor elements may becoupled together to detect a presence of a conductive object over theentire surface of the sensing device. Alternatively, the touch-sensorbuttons 140 may have a single sensor element to detect the presence ofthe conductive object. In one embodiment, the touch-sensor buttons 140may include a capacitive sensor element. The capacitive sensor elementsmay be used as non-contact sensor elements. These sensor elements, whenprotected by an insulating layer, offer resistance to severeenvironments.

The electronic system 100 may include any combination of one or more ofthe touch-sensor pad 120, the touch-sensor slider 130, and/or thetouch-sensor button 140. In another embodiment, the electronic system100 may also include non-capacitance sensor elements 170 coupled to theprocessing device 110 via bus 171. The non-capacitance sensor elements170 may include buttons, light emitting diodes (“LEDs”), and other userinterface devices, such as a mouse, a keyboard, or other functional keysthat do not require capacitance sensing. In one embodiment, buses 171,141, 131, and 121 may be a single bus. Alternatively, these buses may beconfigured into any combination of one or more separate buses.

The processing device 110 may include internal oscillator/clocks 106 anda communication block (“COM”) 108. The oscillator/clocks 106 providesclock signals to one or more of the components of the processing device110. The communication block 108 may be used to communicate with anexternal component, such as a host processor (or host) 150, via hostinterface (“I/F”) line 151, using signaling protocols such as, but notlimited to I2C, SPI or USB. Alternatively, the processing block 110 mayalso be coupled to embedded controller 160 to communicate with theexternal components, such as host 150. In one embodiment, the processingdevice 110 is configured to communicate with the embedded controller 160or the host 150 to send and/or receive data.

The processing device 110 may reside on a common carrier substrate suchas, for example, an integrated circuit (“IC”) die substrate, amulti-chip module substrate, or the like. Alternatively, the componentsof the processing device 110 may be one or more separate integratedcircuits and/or discrete components. In one exemplary embodiment, theprocessing device 110 may be a Programmable System on a Chip (“PSoC™”)processing device, manufactured by Cypress Semiconductor Corporation,San Jose, Calif. Alternatively, the processing device 110 may be one ormore other processing devices known by those of ordinary skill in theart, such as a microcontroller, a microprocessor or central processingunit, a controller, a special-purpose processor, a digital signalprocessor (“DSP”), an application specific integrated circuit (“ASIC”),a field programmable gate array (“FPGA”), or the like.

It should also be noted that the embodiments described herein are notlimited to having a configuration of a processing device coupled to ahost, but may include a system that measures the capacitance on thesensing device and sends the raw data to a host computer where it isanalyzed by an application. In effect the processing that is done byprocessing device 110 may also be done in the host.

The capacitance sensing circuit 101 may be integrated into the IC of theprocessing device 110, or alternatively, in a separate IC.Alternatively, descriptions of the capacitance sensing circuit 101 maybe generated and compiled for incorporation into other integratedcircuits. For example, behavioral level code describing the capacitancesensing circuit 101, or portions thereof, may be generated using ahardware descriptive language, such as VHDL or Verilog, and stored to amachine-accessible medium (e.g., CD-ROM, hard disk, floppy disk, etc.).Furthermore, the behavioral level code can be compiled into registertransfer level (“RTL”) code, a netlist, or even a circuit layout andstored to a machine-accessible medium. The behavioral level code, theRTL code, the netlist, and the circuit layout all represent variouslevels of abstraction to describe the capacitance sensing circuit 101.

It should be noted that the components of the electronic system 100 mayinclude all the components described above. Alternatively, theelectronic system 100 may include only some of the components describedabove.

In one embodiment, the electronic system 100 may be used in a notebookcomputer. Alternatively, the electronic system 100 may be used in otherapplications, such as a mobile handset, a personal data assistant(“PDA”), a keyboard, a television, a remote control, a monitor, ahandheld multi-media device, a handheld video player, a handheld gamingdevice, or a control panel.

The conductive object in this case is a finger, alternatively, thistechnique may be applied to any conductive object, for example, aconductive door switch, position sensor, or conductive pen in a stylustracking system.

Although the foregoing examples have been described in some detail forpurposes of clarity of understanding, the invention is not limited tothe details provided. There are many alternative ways of implementingthe invention. The disclosed examples are illustrative and notrestrictive.

Thus, in one embodiment, a method for operating a capacitance sensingdevice is provided. A capacitive profile of an object proximate to thecapacitance sensing device is detected. The capacitive profile includesfirst capacitance portions and second capacitance portions. At least oneof the second capacitance portions is between two of the firstcapacitance portions. A capacitance value of the first capacitanceportions is greater than a capacitance value of the second capacitanceportions. Data associated with the object is determined based on thecapacitive profile of the object.

In another embodiment, a capacitance sensing device is provided. Thecapacitance sensing device includes an array of capacitive sensorelements and a processing device coupled to the array of capacitivesensor elements. The processing device is configured to detect acapacitive profile of an object proximate to the array of capacitivesensor elements. The capacitive profile includes first capacitanceportions and second capacitance portions. At least one of the secondcapacitance portions is between two of the first capacitance portions. Acapacitance value of the first capacitance portions is greater than acapacitance value of the second capacitance portions. The processingdevice is also configured to determine data associated with the objectbased on the capacitive profile of the object.

In a further embodiment, a capacitance sensing device is provided. Thecapacitance sensing device includes an array of capacitive sensorelements and a controller coupled to the array of a capacitive sensorelements. The controller is configured to detect a capacitive profile ofan object proximate to the array of capacitive sensor elements. Thecapacitive profile includes first capacitance portions and secondcapacitance portions. At least one of the second capacitance portions isbetween two of the first capacitance portions. A capacitance value ofthe first capacitance portions is greater than a capacitance value ofthe second capacitance portions. The controller is also configured todetermine data associated with the object based on the capacitiveprofile of the object. The controller is further configured to at leastone of provide signals to the array of capacitive sensor elements suchthat the array of capacitive sensor elements transmit modulated signalsand demodulate modulated signals received from the array of capacitivesensor elements.

Although the foregoing examples have been described in some detail forpurposes of clarity of understanding, the invention is not limited tothe details provided. There are many alternative ways of implementingthe invention. The disclosed examples are illustrative and notrestrictive.

What is claimed is:
 1. A method of transferring data between a firstdevice and a second device, the method comprising: generating, using anoutput circuit, an analog signal based on a data signal for anapplication associated with the first device and the second device; andtransmitting the data signal over an interface between the first deviceand the second device, the transmitting of the data signal over theinterface comprising capacitively coupling the analog signal through acapacitor formed by at least one sensor electrode, of an array of sensorelectrodes, of the first device and a conductor of the second device. 2.The method of claim 1, wherein the generating of the analog signal usingthe output circuit includes using an output circuit of the first deviceand the transmitting of the data signal includes transmitting the datasignal from the first device to the second device.
 3. The method ofclaim 1, wherein the generating of the analog signal using the outputcircuit includes using an output circuit of the second device and thetransmitting of the data signal includes transmitting the data signalfrom the second device to the first device.
 4. The method of claim 1,wherein the application associated with the first device and the seconddevice is selected from the group of applications consisting of, adevice authentication application, a user identification application, amobile payments application, an access control application, and anelectronic business information transfer application.
 5. The method ofclaim 1, wherein the generating, using the output circuit, the analogsignal based on the data signal includes generating a modulated analogsignal to represent the data signal.
 6. The method of claim 1, furthercomprising: receiving another data signal over the interface between thefirst device and the second device, the receiving of the other datasignal over the interface comprising capacitively coupling anotheranalog signal through the capacitor formed by the at least one of thesensor electrode of the first device and the conductor of the seconddevice; and generating, using an input circuit, the other data signalbased on the other analog signal.
 7. The method of claim 6, wherein thegenerating, using the input circuit, the other data signal based on theother analog signal includes demodulating the other analog signal. 8.The method of claim 1, further comprising, receiving the data signalover the interface between the first device and the second device, thereceiving of the data signal on the at least one sensor electrode of thearray of sensor electrodes.
 9. The method of claim 1, furthercomprising, detecting that a conductive object is proximate to the atleast one sensor electrode of the array of sensor electrodes based on acapacitance of the at least one sensor electrode, the conductive objectbeing at least the conductor of the second device.
 10. The method ofclaim 1, wherein the array of sensor electrodes is arranged as a matrixof perpendicular rows and columns capable of measuring a mutualcapacitance between at a row electrode and a column electrode.
 11. Anelectronic system to transmit data, the electronic system comprising:input/output (I/O) circuitry coupled to a signal generator; and aplurality of capacitance sensing electrodes coupled to I/O circuitry,wherein the I/O circuitry is configured to provide an analog signal fromthe signal generator to at least one capacitance sensing electrode of anarray of capacitance sensing electrodes, wherein the at least onecapacitance sensing electrode is configured transmit the data to anotherdevice through one or more capacitors to be formed by the at least onecapacitance sensing electrode and a conductive element of the otherdevice.
 12. The electronic system of claim 11, wherein at least onecapacitance sensing electrode of an array of capacitance sensingelectrodes is configured to receive data from another device through oneor more capacitors to be formed by the at least one capacitance sensingelectrode and the conductive element of the other device.
 13. Theelectronic system of claim 11, wherein at least one other capacitancesensing electrode of the array of capacitance sensing electrodes isconfigured to receive data from another device through one or morecapacitors to be formed by the at least one other capacitance sensingelectrode and the conductive element of the other device.
 14. Theelectronic system of claim 13, wherein the I/O circuitry is configuredto demodulate an analog signal received on the at least one othercapacitance sensing electrode of the array of capacitance sensingelectrodes and use the demodulated analog signal to provide the data toa device including the I/O circuitry and the plurality of capacitancesensing electrodes.
 15. The electronic system of claim 13, wherein thedata is associated with an application selected from the group ofapplications consisting of, a device authentication application, a useridentification application, a mobile payments application, an accesscontrol application, and an electronic business information transferapplication.
 16. The electronic system of claim 11, wherein the signalgenerator includes at least one of a Universal AsynchronousReceiver/Transmitter (UART), an analog to digital converter, a digitalto analog converter, and a pulse width modulation circuit.
 17. Theelectronic system of claim 11, wherein at least one capacitance sensingelectrode of the plurality of capacitance sensing electrodes is fordetecting that a conductive object is proximate to the at least onecapacitance sensing electrode based on a capacitance of the at least onecapacitance sensing electrode.
 18. A method of transferring digital datato a capacitance sensing device, the method comprising: detecting apresence of the capacitance sensing device to a transmitting device; andresponsive to detecting the presence of the capacitance sensing device,transferring the digital data to the capacitance sensing device, thetransferring of the digital data comprising capacitively coupling ananalog signal through a capacitor formed by the capacitance sensingdevice and the transmitting device.
 19. The method of claim 18, whereindetecting the presence of the capacitance sensing device comprisesdetecting a capacitance change by the transmitting device.
 20. Themethod of claim 18, further comprising generating the analog signalbased on the digital data, wherein the digital data includes at leastone of device authentication information, user identificationinformation, payment information, access information, media datainformation.